This invention relates to an apparatus and method for achieving drying of moist particulate material. The invention will be described for use in conjunction with pulse combustion drying systems, however, other applications of the invention are contemplated and will be apparent to the skilled worker.
An example of a pulse combustion drying system is described in U.S. Pat. No. 5,252,061. As related therein, such systems involve the introduction of moist material into the apparatus, the drying of the material, and the collection of the material from a drying chamber. In a typical application, the material entering the apparatus will be in the form of a pumpable solution or slurry, and the system will result in a dry powder exiting from the drying chamber.
Such a system more specifically comprises the use of pulse combustion for assisting in the drying function. Pulse combustion drying generally relates to the provision of a pulse combustor and associated combustion chamber with fuel being introduced into the combustion chamber. The fuel is mixed with air in the combustion chamber, and this mixture is periodically self-ignited to create high frequency, high energy, sonic pulsations.
A tail pipe is associated with the combustion chamber for achieving release of the hot gases from the combustion chamber on a periodic basis. In the operation of such a system, the momentum of the combustion products issuing from the combustion chamber as a result of ignition and explosion will create a reduced pressure in the combustion chamber to draw in a new air and fuel charge which is again self-ignited to achieve the next explosion. The result achieved with a pulse combustor of this type constitutes a pulsating flow of hot gases issuing from the tail pipe.
In a typical system, the pulsating flow of hot gases is brought into contact with a slurry of material introduced to a material introduction chamber located at the exit end of the tail pipe. Atomization is achieved at this point and drying is continued in the drying chamber positioned downstream of the material introduction chamber.